* Record Chiba rains disrupt transport, knock out power

* About 7,000 travellers stranded at Narita airport

* At least eight killed in flash floods

(Updates figures, adds details; paragraphs 5-8)

By Issei Kato, Hina Suzuki and Mariko Katsumura

OAMISHIROSATO, Japan, Aug 14 (Reuters) - Record rainfall in

Japan stranded thousands of travellers at Tokyo's Narita airport

on Friday, bringing floods to the surrounding area that

disrupted transport, knocked out power to 20,000 homes and

killed eight.

During one of Japan's busiest holiday weeks, more than 360

mm (14 inches) of rain fell in 24 hours in parts of the Chiba

area adjoining Tokyo, inundating roads and railways, with

soldiers sent to help with rescue efforts.

"This case was an extremely unusual situation," Chiba

Governor Toshihito Kumagai told reporters. "I have responded to

many disasters in the past, but I have never experienced a case

like this."

The eight dead included one person trapped in a submerged

vehicle, public broadcaster NHK said, citing Chiba authorities

and police.

At Narita, airport staff distributed sleeping bags, water

and snacks to hundreds of passengers, many of whom had bedded

down on Thursday after transport disruptions stranded about

7,000 people, causing widespread chaos.

"I queued for a taxi, but the wait was four hours," said

Minoru Yamasaki, a 48-year-old Chiba resident returning from

holiday, who had booked a hotel only to be told it could not put

him up. With nowhere else to go, he returned to the airport.

An airport spokesperson said most flights were expected to

operate normally on Friday.

More than 20,000 homes were without power in the early hours

of Friday, after rain flooded a power substation, utility Tokyo

Electric Power said, while gas supply to nearly 13,000 was

temporarily cut.

In Chiba city, one of the worst-hit spots, hundreds of

people spent the night under foil blankets at makeshift

evacuation centres in government buildings.

Some major highways in Chiba were shut, forcing drivers to

take alternative routes that clogged traffic, said highway

operator NEXCO East.

Several rail services were also suspended on Friday, though

some services from Narita to Tokyo resumed, easing congestion at

the international transport hub.

Weather authorities said the 367 mm (14.5 inches) of rain

over a 24-hour period in Chiba exceeded the previous record of

309 mm (12.17 inches) set in October 2013.